carbonara: rewrite lock debug statement
carbonara: rewrite lock debug statement

There's no lock anymore so this should not be logged like that. instead, we
only LOG.debug if we successfully processed the log. The time is not useful
anymore and since log are timestamped, it can be computed if needed anyway.

Change-Id: I40d38985f7a4f3368aeeec56d2b592f64882d1f7

gnocchixyz/gnocchi,leandroreox/gnocchi,leandroreox/gnocchi,sileht/gnocchi,sileht/gnocchi,gnocchixyz/gnocchi